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unknown_cost_value

asked 2015-09-09 09:28:33 -0500

nightblue gravatar image

Im using ROS navigation package, during setting navigation parameters I have seen some used unknown_cost_value parameters by setting 0. I understood by setting it 0 it means robot should assume unknown celss as free, but I wonder what is the general tendency ? Should I set it 0 (FREE_SPACE) or LETHAL_OBSTACLE = 254 or NO_INFORMATION = 255 ? Isn't it awkward if I set unknown_cost_value to NO_INFORMATION=255 ?(why they didnt already set it to 255?)

Thanks.

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answered 2015-09-19 11:56:05 -0500

David Lu gravatar image

This question is ambiguous. The values you quote in the second part of the question are the conventions for costmaps, but you don't specify who the "some" is that is using 0.

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answered 2021-01-11 15:15:56 -0500

Orhan gravatar image

For the future visitors,

I was trying to prohibit the unknown space from planners to plan through, and nothing helped but this parameter in my case.

Basically after setting GlobalPlanner/allow_unknown to false and track_unknown_space: true for costmap layers, the expected behaviour was avoiding the unknown spaces while planning. But it didn't work without setting these parameters for costmaps:

global_costmap:
  unknown_cost_value: 254
  ...
local_costmap:
  unknown_cost_value: 254
  ...

Even though the question was ambiguous, I hope people will find this explanation after googling queries like "setting GlobalPlanner allow_unknown` parameter doesn't work".

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Thank you for your contribution, I am facing the same issue.

zuy gravatar image zuy  ( 2021-12-06 10:33:49 -0500 )edit

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Asked: 2015-09-09 09:28:33 -0500

Seen: 220 times

Last updated: Jan 11 '21